3 Gallon Fish Tank Decoration Ideas (Top 9 With Pictures!)

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Decorating a small 3 gallon fish tank can be tricky, but with some creative ideas you can make it look amazing!

There are lots of cool little decorations perfectly sized for 3 gallon tanks that allow you to build your unique underwater worlds.

all small fish tank decoration items like waterwheel and colorful artificial plants for design inspiration

From brightly colored gravel and rocks to fun tank ornaments and live plants, you have tons of options.

In this post, I’ll share with you the top 9 fish tank decoration themes for a 3 gallon tank to spark your creativity. Ready? Let’s go!

1. Ceramic Pots

a-golden-algae-eater-fish-with-ceramic pot-inside-a-fish-tank
a golden algae eater fish with ceramic pot inside a fish tank

My personal favorite idea! The ceramic pots can make a fantastic decoration for a small 3 gallon tank! This earthy, naturalistic look is great for beginners as well as advanced aquarists.

When using ceramic, be sure to get unglazed terra cotta pots that are safe for aquatic life. You can stack a few tiny, colorful glazed planters together to create height and visual interest. Rest them on their sides or even upside down.

a fish tank well decorated with pots and plants

To finish it off, plant some Java fern or anubias right inside the pots and let their roots spill out. The hardy plants will grow beautifully.

Add a few smooth pebbles or stones around the pots to complete the charming garden scene.

This decoration creates a sort of mini courtyard garden underwater. Feel free to get creative with more pots, some moss balls, and other safe decor stuck or balanced between them like statues or shells. Keep things small-scale though in this compact tank.

cute small fish tank decorated with shells and little pebbles

The terra cotta pots contrast nicely with the gravel, fish, and greenery while giving your betta or small schooling fish lots of nooks to explore! It brings a touch of natural serenity to any space.

2. Artificial Plants

small betta fish tank decorated with artificial plants and pebbles

Decorating a small 3 gallon tank with artificial plants can look really cool. Using soft silk plants adds vibrant color and a natural vibe without needing real maintenance.

I suggest getting brightly colored plastic plants in different shapes and sizes. You can have a look at this resourceful guide on fish tank setup with plastic plants.

Tall grassy ones work to fill in the background. Shorter bushy ones can go midground. And tiny delicate ones make nice foreground details.

Having many sizes and dimensions makes it seem like a lush underwater garden! You can also go with different colors as artificial plants come in many different colors to create a nice background.

cute little glofish tetra and neon tetra in a fish tank

For a 3 gallon tank, I recommend housing Glofish tetras or zebra danios as they will really pop against all the aquarium settings. The plants give them cozy spots to explore and dash around. And meanwhile, you’ll have a great time watching them swimming around.

3. Live Plants

3 gallon well-lit fish tank with live plants and fish swimming inside

If you want a more natural look, then definitely live plants are the way to go.

Live plants give your aquarium a fresh, cool look and help keep the water clean too.

I recommend easy, low-light plants like java fern, anubias, and anacharis.

Attach them gently to decorations like rocks and driftwood using glue. Then, make little plant clusters around the tank. The green leaves and natural wood provides cozy hideaways and exploring spots for the fish.

Having live plants does mean providing proper aquarium lighting and nutrients. But it’s very rewarding watching your underwater garden grow! The plants also give off oxygen to make your fish extra happy.

cherry shrimps and ember tetras in a small live planted aquarium with unique decoration

For a planted 3 gallon tank, I suggest small schooling fish like neon tetras, ember tetras, or rasboras. You’ll really enjoy watching their bright colors dazzle against all that green foliage!

4. Cave Look

aquarium fish looking out from a cave structure inside the fish tank

I also like to go with a natural rock cave look in small tanks. It makes the fish feel safe and cozy.

Start by putting a soft sand substrate on the bottom for a natural look. Then add some good hiding spots. Go to the pet shop and get a couple of nice rocks. It’s easy to create nice caves using Slate rocks as they are flat shaped (which makes them easier to balance one over the other. But you can also choose Lava rock.

For plants, add some Java fern or anubias tied to the rocks. Their broad leaves will give more nooks to explore. 

Add a couple active swimmers like zebra danios, mollies, guppies, or glofish tetras. They will zip around the rock caves and plants, with their bright colors popping against the dark rocks. The cozy cave decor makes them feel secure to come out and play!

A 3 gallon rock cave tank like this takes little work but looks sweet.

5. Air Stone

small fish swimming in a live planted aquarium with bubbles from air stone

Now if you’re looking for a fun themed small fish tank decoration idea, then you’ll really like the idea of decorating with air stones and a sponge filter. It creates a nice bubbles-filled environment that your fish will enjoy.

Air stones are small decorative pieces that you connect to an air pump that will send a constant stream of bubbles throughout your tank. Add one or two of these with a simple sponge filter, which both filters the water and creates a gentle flow, and your tiny 3 gallon tank will be alive with dancing bubbles!

This type of setup with plenty of water circulation and surface agitation works well for betta fish or small tetra species.

Especially, bettas like to swim around bubbles. You can also keep other fish like mollies, or cory catfish. And if you have a goldfish tank, then that would work well too.

For decor, keep it simple – a few artificial, soft silk plants and a small centerpiece decoration like a stone ruin or sunken ship will be good enough.

6. Moss Balls

a small well-lit 3 gallon tank with beautiful fish and decorated with moss balls

Moss balls make for a fun and easy way to decorate a small 3 gallon fish tank. These neat little bundles of green add a pop of color and interest without taking up much space.

Moss balls, also called Marimo balls, are a type of algae that grows in a round – cute ball-like shape. They make low maintenance additions to aquariums because they don’t require special lighting or fertilizers.

In a 3 gallon tank, place 2-4 moss balls scattered around the tank. Add a few light-colored mollies.

Two white mollies swimming in a well decorated small planted fish tank

Now, mollies have the habit of nibbling from plant matter. So it would be a great sight when they will nibble the moss balls or live plants and just swim around inside the tank.

You can also add cory catfish varieties like albino cory catfish, and panda cory catfish which look pretty in the tank.

The soft green color complements brightly colored gravel and decor well. It also provides nice contrast if you add darker cave or hut structures for fish to hide in. 

This simple yet eye-catching moss ball aquascape is perfect for beginner fish hobbyists, children’s rooms, or desktop tanks. It creates a nice natural look without much effort.

7. Character Like Scuba Diver As Centerpiece

a black molly fish with pleco and some small snails inside a small fish tank tank decorated with a centerpiece house decoration

Got a 3 gallon tank and want something totally unique? Make a scuba diver the star of your underwater scene!

Miniature scuba figures designed for small aquariums make for awesome centerpiece decorations.

Pop a little Scuba diver toy right in the middle of your tank and build your theme around it.

These divers come in in fun bright colors and look cool in the dark!

You can place your Scuba diver right on top of the gravel or attach him to a piece of small driftwood or decorative rock using aquarium-safe glue.

This scuba diver decoration is perfect for kids or adults who want a playful, adventurous tank theme. It’s an eye-catching conversation starter for office, classroom, or home aquariums.

And your fish will keep circling around this centerpiece curiosity too! Just make sure to give them enough open swimming room.

You can also add some colorful gravel or aquarium sand to mimic the sea floor.

For fish, small tropical species like neon tetras, guppies or bettas would look perfect. 

The bright colors of the fish and decorations will contrast nicely with the little scuba dude exploring the tank.

8. Sunken Ship

sunken ship inside a fish tank

Another great idea is to decorate the fish tank with a sunken ship as a centerpiece.

Okay, so what you’ll do is grab a little shipwreck ornament from the pet store.

Dip it right there in the middle of the tank. Then sprinkle gravel, tiny rocks, and sand around the edges to make it seem buried.

You can also add other toys around the ship that match with the main underwater theme. 

To complete the look, use colorful fish that’ll really stand out. For instance, I’m talking guppies with their big colorful tails, glowlight tetras with their neon color body, and bettas with flowing fabulous fins.

When they swim in and out of the sunken ship, it just becomes alive!

9. Background Poster

If you’re looking for the most affordable and easy way to decorate your small fish tank, then adding a background poster is the best way to go.

In pet stores, you’ll easily find these background posters that stick to the outside back wall of the tank. Since fish tanks are made of transparent glass or acrylic, the poster pops up from behind creating a nice theme, adding a new charm to the whole aquarium.

These posters come in various themes; one popular option is the coral reef theme. So even if you have a freshwater tank, you can create a pretty underwater sea look with these posters.

Now, you can either keep the tank simple with just the poster background, substrate and a few colorful fish like neon tetras or maybe even add a few snails or shrimp.

But if you want, you can further decorate with a cool small air stone that adds a beautiful bubble stream inside the tank. Or put a hollow pipe or cave toy to create hiding places for the fish.

a cool small fish tank with plants and school of small fish

Speaking of fish tanks, have you ever wondered what it would look when you place a fish tank under a TV? 👈 Check out my guide to learn more.

Final Words…

There are lots of creative ways you can decorate the 3 gallon fish tank.

From brightly colored gravel and lively air stones to charming terra cotta pots and playful sunken ships, you can craft all kinds of eye-catching looks.

With a thoughtful mix of shades, textures, and dimensions, it’s easy to design a one-of-a-kind 3 gallon habitat your fish will enjoy.

So explore different themes and don’t be afraid to think of creative ideas to decorate your small fish tank. Before you know it, you’ll have a gorgeous, lively showpiece!